**Question:** Herpetic keratitis is treated by

A. Corticosteroids
B. Antiviral agents
C. Topical antibiotics
D. Cycloplegics

**Correct Answer:** B. Antiviral agents

**Core Concept:** Herpetic keratitis is an inflammation of the cornea caused by the herpes simplex virus (HSV). The virus belongs to the Herpesviridae family and has two subtypes: HSV-1, which primarily affects the oral cavity and face, and HSV-2, which affects the genitals.

**Why the Correct Answer is Right:** The correct answer, antiviral agents, are used to inhibit the replication of the virus and reduce the severity of the inflammation. Herpetic keratitis is typically treated with acyclovir, an antiviral medication that targets the viral DNA polymerase, a key enzyme involved in viral replication. Acyclovir is converted to its active form, aciclovir, within the infected cells, where it inhibits the viral polymerase, thereby preventing the replication of the herpes simplex virus.

**Why Each Wrong Option is Incorrect:**

A. Corticosteroids: These immunosuppressive drugs are sometimes used in the initial phase of herpetic keratitis to reduce inflammation and pain. However, long-term corticosteroid use may exacerbate the herpetic infection by promoting viral replication and reactivation.

B. Topical antibiotics (e.g., fluoroquinolones): While antibiotics can help manage bacterial superinfections, they do not address the primary viral infection caused by herpes simplex virus. Herpetic keratitis is a viral infection, and using antibiotics is not the appropriate treatment.

C. Topical cycloplegics (e.g., cyclopentolate): Cycloplegics are used to dilate the pupil and are not relevant to treating herpetic keratitis, which is a viral infection caused by the herpes simplex virus.

**Clinical Pearl:** Early initiation of antiviral therapy, specifically antiviral agents like acyclovir, is essential in managing herpetic keratitis to prevent complications and reduce the risk of vision loss. Timely treatment can also reduce the duration of the infection and decrease the risk of secondary bacterial infections.